A practical consequence of national conversion to a full metric system of weights and measures is the widespread need that it creates to modify certain equipment to accommodate the new system. Such a need exists in countries such as the United States and Canada, where gasoline has historically been dispensed in either U.S. or Imperial gallons.
From the mechanical standpoint, it is of course a relatively simple matter to alter the mechanisms of existing gasoline dispensing pumps, so as to change the ratios to reflect the volumetric relationship between gallons and liters. Since, however, the avoidance of undue confusion will necessitate introduction of such a liter-based dispensing system uniformly throughout the affected regions, preparations must be made to convert large numbers of pumps at virtually the same time. To enable ongoing operation, moreover, the pumps must be adapted to dispense gasoline on a gallon basis until the time for conversion arrives, at which time the means must be in place to enable quick and easy conversion to the liter mode.
The need for such a device has previously been appreciated, and numerous attempts have been made to satisfy it; for example, variator input-modifying gear boxes have been proposed for that purpose in U.S. Pat. Nos. 3,938,736, and 3,943,340. While the concept underlying that approach to the problem is sound, the mechanisms implementing it are rather complex. Moreover, in the device of U.S. Pat. No. 3,943,340 it is found possible to achieve a neutral position in which the pump can be operated without causing the computer to register. Finally, the slide used therein to effect conversion would not accommodate a seal in the shifted position, and has a tendency to break.
Accordingly, it is the primary object of the present invention to provide a novel assembly for installation in a fuel dispensing pump, or the like, to convert the computer thereof to a modified volumetric basis for the dispensing function.
It is a more specific object of the invention to provide such an assembly which is adapted to render the pump capable of operation in either the gallon-based or the liter-based mode, and in which the conversion is effected quickly, simply and at no cost.
Another object of the invention is to provide such a device having tamper- and accident-resisting features, enabling facile intentional conversion from gallon to liter units while permitting reversal only with considerable difficulty.
Yet another object of the invention is to provide an assembly having the foregoing features and advantages which is also of uncomplicated design, rendering it dependable, easy to install and service, and relatively inexpensive to manufacture